/*
 * Copyright [2013-2021], Alibaba Group Holding Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.polardbx.executor.cursor;

import com.google.common.util.concurrent.ListenableFuture;
import com.alibaba.polardbx.optimizer.config.table.ColumnMeta;
import com.alibaba.polardbx.optimizer.core.row.Row;

import java.util.List;

import static com.alibaba.polardbx.executor.operator.ProducerExecutor.NOT_BLOCKED;

/**
 * Cursor Interface
 */
public interface Cursor {

    Row next();

    /**
     * 关闭结果集游标
     */
    List<Throwable> close(List<Throwable> exceptions);

    /**
     * 获取该cursor返回的所有列
     */
    List<ColumnMeta> getReturnColumns();

    default boolean isFinished() {
        return false;
    }

    default ListenableFuture<?> isBlocked() {
        return NOT_BLOCKED;
    }
}
